Eevee renderer bug or intentional?
Just a guess, but it looks as if the light in your scene may be set with too high a strength, washing out the results. Check to see what the strength setting is on your light by selecting it in Object Mode and looking at the Object Data tab in the Properties Panel. You can also turn on the rendering viewport setting by holding the z key and choosing Rendering from the pie menu popup. Changing this setting will allow you to see what you can expect visually from your adjustments to this light before committing to an actual render. Hope this helps.